Emerging detection of carbon-based gases with multiple bonds by activating MoO bonding in Na, Sb-codoped NiMoO4

Exhausting carbon-based gases from building construction or comfortable household supplies have caused the main pollution gas species for the indoor air environment. Given the variety of indoor activities, many reports have been challenged to find room-temperature operational and harmless materials. Here, we report that the activating MoO vibration mode in Na,Sb doped-NiMoO₄ micro-sized powder reveals the high response of CO and VOC, occupying multiple bonds at room temperature. We performed Na and Sb doping in the α-NiMoO₄ crystal structure, such as introducing the Sb in Ni and interstitial doping of Na in around 4 Å of free space in the NiMoO₄ crystal structure that manipulates the partial β-NiMoO₄ phase. The Na,Sb-codoped NiMoO₄ generates the higher MoO vibration mode from FT-IR measurement and enables carbon-based gas detection with 38 responses to CO and nearly 20 responses to VOC under 20 ppm of each analyte gases environment. Furthermore, the n-type gas sensing behavior of Na,Sb doped-NiMoO₄ chemiresistor exhibits an immediate sensing response instead of a none-of response than intrinsic or single element doped NiMoO₄. These results suggest that Na,Sb codoped-NiMoO₄ is the applicable material for emergent warning against carbon-based gas exposure in the indoor environment. In addition, activating the electrochemical reaction site of MoO₄^–2 in NiMoO₄ is tailorable by a simple doping process.